Storage tanks of flammable liquids, such as petroleum products are commonly grouped or clustered together in an area referred to as a "tank farm". Should one of the tanks become ruptured and the contents become involved in a fire, huge quantities of heat are generated. The heat generated in the fire radiates into the surrounding tanks and their contents.
The radiated heat weakens anearby tank's outer shell and creates internal pressures, especially as the tank's contents rise in temperature. Then the rise in temperature makes the tank more vulnerable to rupture.
The most common fire fighting technique is to cool the external shell of any surrounding tanks in the tank farm which might be susceptible to extreme heat.
The most frequent cooling technique conducted is to spray large quantities of water on the tank shel. The cooling water (fire stream) is sprayed directly under high pressure onto the side of the tank.
However, the high pressure water hits the tank with such force that the wate immediately bounces back off the face of the tank. As a result, the water is in contact with the tank skin for only a short time and is very inefficient in transferring heat because of this limited contact with the tank skin.
Moreover, the fire fighter must position himself as directly as possible between the tank that is on fire and the tank that is to be cooled. Such as position is necessary in order for the fire fighter to direct his cooling water (fire stream) directly at the face of the tank skin that is receiving most of the radiated heat from the tank that is on fire.
Some of the prior provides the following references:
U.S. Pat. No. 1,220,106, Hartenberger, Mar. 20, 1917 PA1 U.S. Pat. No. 2,955,686, Blomeley et al, Oct. 11, 1960 PA1 U.S. Pat. No. 2,994,383, Gorand et al, Aug. 1, 1961 PA1 U.S. Pat. No. 4,044,517, Schroter, Aug. 30, 1977 PA1 U.S. Pat. No. 4,177,863, Simon, Dec. 11, 1979 PA1 GB No. 2,000,022, Winkler, Jan. 4, 1979 PA1 WIPO No. 83/01200, Sobrinho, Apr. 14, 1983
U.S. Pat. No. 1,220,106 to Hartenberger describes a wooden silo having a double wall construction comprising an inner lining and an outer sheathing constructed so that there is a space between them to provide for free circulation of air from air inlet doors in the bottom of the silo upwardly to an exit space provided in the conical roof of the silo.
U.S. Pat. No. 2,955,686 to Blomeley et al described a double-walled insulating structure for gasoline, fuel oil, chemicals, and similar products. In the enclosed space between the two walls, insulating material is inserted to be held in place by a series of supporting members and distance members. The insulating material, such as fiberglass or the like, also fills the space provided in the domed roof which is secured to the walls.
U.S. Pat. No. 2,994,383 to Gorand et al describes a fire protection system for an elevated structure, such as a tower, vessel, or building. The system includes a fixed nozzle, mounted generally at ground level, attached to a high pressure water system, and directed at a "chute", or water receiving member. The chute has an enlarged water receiving inlet and a restricted water outlet. The water outlet of the chute is connected to a water distribution pipe which receives the water which had been directed into the chute and permits the water to exit the pipe through a series of opening in the pipe so that water will be distributed over the surface of the elevated structure.
U.S. Pat. No. 4,044,517 to Schroter describes a tank jacketing system for a cylindrical tank comrpising a series of circular track components to which are attached individual panel members, vertically attached and with each panel member insulated with a rigid insulating member adhesively attached to the inner side of the panel. The arrangement is for heat-protecting the storage tank. The panel members and wall of the storage tank are loosely secured at the top of each by a coping disposed over the exterior of the insulating wall and innermost upper portion of the wall of the storage tank.
U.S. Pat. No. 4,177,863 to Simon describes a safety liquid dispenser which provides a combination a double walled tank body comprising an intermediate container of flammable liquid and an inner tank disposed within the intermediate container and containing pressurized carbon dioxide positioned to smother any flame condition occurring within the tank.
GB No. 2,000,022 to Winkler describes a fire-resistant container for combustibles comprising a double-walled container with the space between the walls filled with fire-extinguising material.
WIPO No. 83/01200 to Sobrinho describes a trough-like collar affixed to an upper external rim of a fuel tank which includes a plurality of overflow holes. A water supply pipe is in position to supply water to the trough of the collar from which the water may exit the holes and flow down the side of the tank.